Arc control device



Aug. 15, 1944; D. ELLIS ET AL ARC CONTROL DEVICE Filed July 31, 1942 and |NVENTOR5 .De/erf 5/03 oBWfiwl. /o

ATTORNEY \VNITNESSES:

Patented Aug. 15, 1944 ARC CONTROL DEVICE Delbert Ellis and Owen L. Taylor, Wilkinsburg, Pa., assignors to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application July 31 1942, Serial No. 453,059

Claims.

This invention relates to an are limiting device and, more particularly, to improved structure for moving an are drawn between two contact members into deionizing grids where it may be extinguished.

The manner in which deionizing grids function to break up and extinguish an are drawn between two contacts is well known. Patent No. 1,932,090, issued October 24, 1933, to Joseph Slepian may be referred to as an example of an arc extinguishing structure employing deionizing grids and for the theory of operation of such grids. In the use of such grids for extinguishing an arc, it is necessary to provide a means for moving the arc with suflicient rapidity to and into the grids before damage has been done to the contacts, and before 'an amount of ionized gas sufficient to cause failure in another part of the switch, or suflicient to interfere with the function of the grids, has been evolved.

Various arrangements have been employed for the urpose of moving the are away from the contacts and into the grids where it may be extinguished. Obviously, a magnetic blow out coil and like conventional devices for moving an arc may be employed for this purpose. However, the elimination of such devices wherever possible is desirable for the reason that they are expensive to manufacture and occupy an unreasonably large amount of space.

One of the principal objects of this invention is to provide an improved arrangement of structure for moving an arc toward and into deionizing grids which will be inexpensive to manufacture and will occu y a minimum of space.

A further object is to provide a device which will distort the path of an are drawn between two contactmembers and thereby produce a magnetic field for moving the arc toward and into the grids.

Other objects and advantages of this invention will become apparent from the following description and the accompanying drawing in which:

Figure 1 is a vertical sectional view of a circuit interrupting device constructed in accordance with the principles of this invention;

Fig. 2 is a view similar to Fig. 1 illustrating a modification; and

Fig. 3 is a perspective view of the U-shaped metallic arc control device shown in Fig. 1.

In the drawing numeral l designates a housing formed of insulating material having a cavity 2 and an opening 3 formed therein and communicating with such cavity. Conducting members l and 5 are mounted in the housing I and are respectively provided with stationary contacts 6 and l at the upper portion of the opening 3 adjacent the cavity 2. A bridging member 8 having a air of movable contacts 9 and I0 respectively engageable with the stationary contacts 6 and I is mounted on a saddle ll connected to an operating member I! for moving the contacts 9 and I0 back and forth in the opening 3 between positions engaging and disengaging the contacts.

A plurality of deionizing grids l3 are mounted in position in the cavity 2 for extinguishing an are drawn between the contacts 6 and 1. The above mentioned patent to Slepian may be referred to for an understanding of the construction and theory of operation of the grids l3.

In the showing of Fig. 1 the two end grids l3 are provided with extensionsor arc horns H which extend angularly and downwardly from the front edges l5 of the grids to points adjacent the stationary contacts 6 and l. A U-shaped member it, best shown in Fig. 3, is mounted transversely of the cavity 2 with its closed end ll positioned substantially centrally of and between the stationary contacts 6 and l. The parallel sides or limbs it of the U-shaped member I6 at the open end thereof provide the two central grids shown in Fig. 1. That is, these links ii are coextensive with the grid plates l3 and lie in parallel thereto so as to form part of the grid plate arrangement.

Upon operation of the member I! to disengage the movable contacts 8 and ID from the stationary contacts 6 and I, an arc will be drawn which will join across the contacts 6 and 1 when the resistance of the path across the contacts 6 and 1 is less than the resistance of the path from the contact 6 to the contact 9 and through bridging member 8 and contact III to the contact I. At the time the current path is completed directly from the stationary contact 6 to the stationary contact I arcs will strike between the lower ends of the members I and the contacts 6 and 1 and between the members I and the outer surfaces of the parallel sides l8 at the closed end H. The current path at such time will be as indicated by the lower set of arrows as shown in Fig. 1. Attention is invited to the fact that the arcs striking to the closed end ll splits the are intermediate the contacts 6 and 1 into two portions, which are electrically connected by the current flowing through the semicircular portion of the closed end H. The current flowing through such semi-circular portion forms current will follow the path as irrdioatedb! the upper set of arrows andthe arcs will be driven into the grids l3 where they will be extinguished.

to that shown in Fig. 1

and have their tioned adjacent the stationary contacts 6 and I; In this construction a single arc will strike between the closed ends in such closed ends will form partial loops, .there-- by creating strong fields at the points A which will be effective to drive the ends of the are upwardly along thecontinuous surfaces 49 and into the grids l3.

In both modifications the shape of the closed ends I1 and the'mannerin. which the current flows therethrough is effective to distort thepath of the current fiowingbetween the stationary contacts. driving the are are providedby causing the cur rent to flow in a partial loop, a current' fiowing in a loop or partial loop having a strong magnetic field at its center and a weaker field'on its outside.

From the foregoing, it will be apparent that the U-shaped members I6 and'the manner in which they are employed to distort thepath' of an are drawn between the contacts'li and? are effective to provide a magnetic field for driving the are into deionizing grids. Itwill also be apparent that the structure providing such field is inexpensive to manufacture and install and requires a minimum of space.

Since numerous changes may be made'ln the above described construction and difierent'em bodiments of the invention may be made Without departing from the spirit and scope thereof, it is intended that all the matter contained in the foregoing description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

We claim as our invention:

1. In a circuit breaker having contacts for drawing an arc, and an arc quenching means, said means comprising a set of grid plates dis posed substantially in parallel and in spaced relation to each other andljextendingsubstantially at right angles'to the are tobe'quenched, and a substantialWU-sharied arcingv member having a loop portioriintegralwith two limbfpor-,

tions, said loop portion projecting'o'ver saidset" toward said contacts to form "an'arcing horn and said limb portions extending continuously from said 100p portion into said set in parallel and in spaced relation to said plates.

2. In a circuit breaker having contacts for drawing an arc. and are quenching means, said means comprising, in combination, a set of individual grid plates of flat shape disposed subl1 and the current flowing The structure illustrated in Fig. 2 is similar and like numerals nave been employed to designatelike. parts., In this V showing two U-shaped members-l5 are employed closed ends ll respectively-p051 drawing an are.

shaped members disposed v speptivelyuof' said are in onrertp cause the current flowing in said loop portions-when drawing an arc to coact with the current in the arc to produce a magnetic field for moving the are into said set.

3. In a circuit breaker having contacts for and are quenching means, said means comprising, in combination, a set of individual grid plates disposed substantially in parallel and in spaced relation to each other and extending.substantially at right angles to the are to be quenched, and two substantially U- at the ends respectively of said set and having each a loop portion a integral with two limb portions, said limb portions being arrangedinparallel to said plates so astofo'rm acontinuation of said set. and said In this manner, magnetic fields for drawing an arc,

loop portions projecting from said set toward said-contactsv soasto lie close to the ends respectively of saidarc in order to form arcing horns. said' setmeasured ata right angle to said plates'b'eing longer than the separating distance of said contacts and said loop portions being inclinedto'wards each other. so as to lie close to the ends respectively of the arc to be drawn by said contacts.

4. In a circuit, breaker having contacts for and arc quenching means, said means comprising, .in combination, a set of flat n'd plates disposed substantially in parallel and in spaced relation to each other and extending -Isubstantiallyiat right angles to the arc to be quenched, and asubstantiallyU-shaped arcing .membenarrangedcentrally between said. plates and having a loop portion and two limb portions.

said loop portion projecting from said plates toward andinto the path of said are to split it into two arc portions, and said limb portions extending continuously from said loop portion into said .set in parallel to said plates. said set having its 1 two outer plates projecting over the other plates .close to v ,horns for moving said are portions between the toward said contacts the projecting portions of said outer plates, respectively being inclined .toward each otherand having their ends disposed said contacts in? order to form arcing "adjacent platesof said set.

5, A doublebreak circuit interrupting device comprising an arc-deionizing structure having a setof; spaced grid plate of flat shape. a pair of stationary contacts spaced from said'set substantially in parallel to the spacing direction of said stantially in parallel and in spaced relation to each other and extending substantially at right angles to the arc to be quenched, and two substantially U-shaped arcing members disposed at continuous arc guiding surfaces, whereby plates, a bridging member having a pair of contacts disposed for e agement with said stationary contacts and m ovable substantially at right .angles, to said direction, and a conductive U- shaped member having a looped end positioned centrally between said stationary Contacts and two limb portions extending from said end towardand betweenv said grid plates so as to form an are occurring between said stationary contacts is I split into two are portions and moved along said between said plates. DELBERT ELLIS. OWEN L. TAYLOR.

limb portions toward and 

